Bold type, also known as boldface, is a typography style characterized by the use of a thicker line in the text. There are various ways to represent it: typography, typing, word processing, HTML, CSS, and wiki formatting. It is most often used to highlight or emphasize a specific part of the text.
John Mueller, Google's senior webmaster trends analyst, stated that bold words and important points in a paragraph help with SEO, in addition to tags used to classify content. Likewise, the professional explained that it's necessary to only highlight the important text; that is, if all the text is bolded, it won't help at all.
“Another thing is that this is largely relative within the website. If you go and say, 'Well, I'll just put my entire page in bold,' and then you'll think that Google will think that page is the most important, then by putting everything in bold, essentially nothing is bold because everything is the same,” the Google employee added.
While this use is important, it doesn't directly impact the page's ranking, but rather becomes a positive element for the blog post's scannability. Therefore, its conscious use, highlighting only the essential, gives a plus to your website and the writing on the web.